Method for manufacturing grinding wheel having depressions on grinding surface thereof

Abstract

A grinding wheel is manufactured such that (a) any one of particles for an abrasive grain layer and particles for a substrate layer are put into the press-mold die, and other particles are put onto the particles in the press-mold die, and then the substrate layer and the abrasive grain layer are integrally press-molded to form a non-baked grinding chip with an arcuate shape; (b) depressions are formed on the abrasive grain layer of the non-baked grinding chip; (c) the grinding chip on which the depressions are formed is baked; and (d) the plurality of baked-grinding chips are adhered to a core of the grinding wheel.

The invention claimed is: 
     
       1. A method for manufacturing a grinding wheel having depressions on a grinding surface thereof, which comprises a plurality of grinding chips that include a substrate layer and an abrasive grain layer containing superabrasive grains, wherein the grinding chips are adhered to a core mounted to a wheel spindle that is rotatably journalled in a wheel head of a grinding machine, and the grinding surface formed on the abrasive grain layer contacts with a workpiece, which is rotatably supported on a workpiece supporting apparatus of the grinding machine, to grind the workpiece at a grinding point, wherein the method comprising the steps of:
 forming the grinding chip before baking whereby a substrate layer formed by mixing substrate grains with bond is overlaid on an inner surface of an abrasive grain layer and is integrally press-molded with the abrasive grain layer to form the grinding chip with an arcuate shape, wherein the abrasive grain layer is formed by mixing superabrasive grains with the bond; 
 forming a plurality of depressions on an abrasive grain layer of the non-baked grinding chip using forming elements made of a combustible material; 
 baking the non-baked grinding chips in an atmosphere capable of combusting the forming elements made of a combustible material and at a temperature sufficient to combust the forming elements, thereby making baked grinding chips; and 
 adhering a plurality of baked grinding chips to the core such that the grinding chips are circumferentially arranged on a radially outer periphery of the core, wherein the depressions are inclined grooves that are inclined relative to the circumferential direction of the grinding wheel, and 
 wherein the inclined grooves are provided on the grinding chips with such a spacing and inclination that at least one of the inclined grooves always passes through a grinding point of the grinding wheel when the grinding wheel is rotated about a wheel axis of the grinding wheel to grind a workpiece at the grinding point. 
 
     
     
       2. The method for manufacturing a grinding wheel according to  claim 1 , wherein the inclined grooves reach to the substrate layer from the grinding surface. 
     
     
       3. The method for manufacturing a grinding wheel according to  claim 1 , wherein:
 at the time when the press-molding is performed, 
 disposing a plurality of inclined groove forming plates for forming the inclined grooves at a grinding surface forming surface of a press-mold die for molding the grinding chip, wherein the inclined groove forming plates are the forming elements made of a combustible material, are made of carbon or resin, and are respectively inclined relative to a direction corresponding to the circumferential direction of the grinding wheel where the grinding chips are to be adhered to the core thereof; 
 putting particles for the abrasive grain layer into the press-mold die, and putting particles for the substrate layer onto the particles for the abrasive grain layer to be overlaid on the abrasive grain layer in the press-mold die, wherein the particles for the abrasive grain layer is formed by mixing the superabrasive grains with the bond, and the particles for the substrate layer is formed by mixing substrate grains with the bond; 
 integrally press-molding the particles for the abrasive grain layer and the particles for the substrate layer, whereby the substrate layer to be formed is not divided by the inclined groove forming plate; 
 removing the non-baked grinding chip from the press-mold die, wherein the abrasive grain layer and the substrate layer are integrally press-molded in a state that the inclined groove forming plates penetrate through the abrasive grain layer; and 
 at the time when the chip baking is performed, 
 forming the baked grinding chip by baking the grinding chip in an atmosphere capable of burning away the inclined groove forming plates while the grinding chip is baked, and thereby the inclined grooves inclined relative to the circumferential direction of the grinding wheel are formed on the abrasive grain layer.